Nortel Networks Corporation

John M Williamson

Anthony K Brown

Terry E Newell

Alexandre J Guterman

Robert Zani

A signal transmission device including an input for receiving an input electrical signal containing a succession of pulses. The input signal has a high data rate, preferably in excess of 10 gigabits per second. The signal is split in two identical specimens, referred to as first signal and second signal and injected in respective channels of a lossy transmission path whose function is to carry the signals to an intended destination. Before introducing the second signal in the respective channel of the lossy signal transmission path, a negative DC shift is applied to the second signal. During the transmission of the first and the second signals through the lossy signal transmission path, they are subjected to distortions that cause the leading and the trailing edges of pulses in the signals to spread out. To compensate for this distortion, the first and the second signals are processed at the destination by first and second functional units that comprise non-linear signal transmission paths. The first functional unit effects compression of the leading edge of the pulses in the first signal while the second functional unit effects compression of the trailing edges of pulses in the second signal. The outputs of the functional units are combined into one signal containing the pulses from the input signal but substantially free of the distortions introduced by the lossy signal transmission path.

Method and apparatus for transmitting an electrical signal featuring pulse edge compression

The invention is a non-contact coupling system for use in interconnecting a large number of electronic modules to a main signal trace via non-contact couplers. A driver sends an electronic signal comprising pulses along the main signal trace. The couplers each have a track of conductive material substantially parallel to the main signal trace. The track of each succeeding coupler is longer than that of the preceding coupler. As a pulse travels from the driver alongside the track of the closest coupler, a pulse is induced therein, although part of the original pulse energy is lost. The remaining lower-energy pulse then couples onto the second-closest coupler but because of the longer parallel track, an induced pulse virtually as strong as the pulse imparted to the first coupler is produced. This phenomenon occurs at every coupler along the main signal trace, resulting in induced pulses that have a relatively low amplitude variation.

Non-contact coupling system

A bus for high signal quality interconnections, comprising means for producing at least one common mode reflection, often for differential transmission line interconnections. Also, a bus for high signal quality interconnections further comprising means for under-damping the signal and/or reducing the common mode noise. In both cases the means are at least one impedance termination. To produce common mode reflections, there are non-contact couplers terminated by short and open circuits, which cause the reflections from via connectors and other like impedance discontinuities to be re-reflected in common mode so that they are rejected by a differential receiver. To produce under-damping of the signal and/or a reduction of the common mode noise, capacitive terminations are used. The under-damping of the signal sharpens in the falling edge of the coupler pulses.

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Stittsville, Canada

John M Williamson